(a) Field of the Invention
The present invention relates to a trimethylolpropane ester-based plasticizer composition, and more particularly to a trimethylolpropane ester-based plasticizer composition used as a plasticizer when preparing polyvinyl chloride resin.
(b) Description of the Related Art
Polyvinyl chloride (PVC) is a general resin that can attain various physical processing properties by suitably mixing additives such as stabilizers, fillers, pigments, and plasticizers. Polyvinyl chloride with the various physical processing properties is widely used as a material for goods such as wallpaper, gloves, and toys, as well as for pipe, electric wire insulation, and artificial leather. The plasticizer is an essential additive for preparation of polyvinyl chloride resin, to impart various physical properties such as processability, flexibility, electric insulating ability, etc.
The representative plasticizers used in processing of polyvinyl chloride resin include phthalate-based plasticizers, adipate-based plasticizers, and trimellitate-based plasticizers, etc. The most generally used plasticizer, di-2-ethylhexylphthalate (DEHP), is phthalate-based, and it plays a role as a standard plasticizer for performance evaluation of other plasticizers.
On the other hand, trimethylolpropane ester is mainly a well-miscible lubricant for refrigerants, (U.S. Pat. No. 5,470,497), and it is also used as an additive for lubricating oil in automobile engines (U.S. Pat. No. 4,061,581). Furthermore, trimethylolpropane ester can effectively remove precipitation materials from metal surfaces in engine parts of automobiles (Japanese Patent Laid-open Publication No. Heisei 5093191 A2), and an ester prepared by synthesis of trimethylolpropane and fatty acids improves friction resistance of a road surface without reduction of friction resistance of a wet road (Japanese Patent Laid-open Publication No. Heisei 1113444 A2).
Although the trimethylolpropane ester is used as an additive for lubrication as mentioned above, it has structurally weak physical properties compared with phthalate-based and trimellitate-based plasticizers widely used in the related art, and thus it is not used as a plasticizer when processing polyvinyl chloride.
For example, as a plasticizer used in processing of polyvinyl chloride resin, trimethylolpropane ester comprises mono-component esters each synthesized by adding hexane or 2-ethylhexanoic acid as an acid of an aliphatic group series, or benzoic acid as an acid of an aromatic group series, to trimethylolpropane as a triply-charged alcohol.
In addition, triethanolmethane ester is a plasticizer having physical properties superior to trimethylolpropane ester or other plasticizers. The trimethylolpropane ester was inferior in physical properties, as mentioned, as the ester of the mono component has too many weak bonds to play a role as a plasticizer, even in the case when compatibility with polyvinyl chloride resin does not exist (U.S. Pat. No. 3,939,201).
It is an object of the present invention to provide a trimethylolpropane ester-based multi-component synthesized plasticizer composition by adding benzoic acid as an aromatic acid and aliphatic mono-carboxylic acid with 3 to 10 saturated linear or branched carbon atoms to trimethylolpropane as a triply-charged alcohol so that a polyvinyl chloride resin body having superior tensile strength, elongation, migration resistance, and sheet heating loss etc. can be prepared by using it as a plasticizer during polyvinyl chloride resin processing.
In order to achieve the object, the present invention provides a plasticizer composition comprising trimethylolpropane ester shown in the following Formula 1: 
wherein R1, R2, and R3 are a phenyl group or an alkyl group with 3 to 10 and preferably 4 to 5 carbon atoms, respectively.
Furthermore, the present invention provides a polyvinyl chloride resin body comprising the plasticizer composition.